TERATOLOGY IN MODERN BOTANY. 99 



strangest fashion, just as are the peculiarities of two different 

 species in their hybrids. 



The malformations caused by animals show us, as a 

 matter of fact, that the development of organs is modified by 

 material influences, although, as has been said, the range 

 of those modifications is naturally limited by the peculiari- 

 ties of the particular plant. The fact that they are of such 

 frequent occurrence in the flowers, and relatively rarely are 

 found in the roots, for example, may be due to the following 

 peculiarities : — ^ 



1. The organs arise at the vegetative point of the in- 

 florescence in rapid succession, and usually in considerable 

 number, close above and by the side of each other. 



2. There are thus formed at short intervals oro-ans of 

 varied structure, e.o-., petals, stamens, etc. 



3. Comparatively slight disturbances would thus suffice 

 to call forth changes in the arrano^ement as the oroan- 

 forming materials are supplied, since the normal develop- 

 ment of parts of so complicated a character can only occur 

 when the supply of material and the phenomena of cell- 

 division occur with almost mathematical exactitude. If, for 

 example, a few molecules of the material which gives rise 

 to the growth of anthers were diverted to the right or left 

 to the extent of the thousandth of a millimetre, or were to 

 be delayed or accelerated upon their journey in the apical 

 region of the inflorescence, the characters of a stamen might 

 be partially assumed by a petal or a carpel. 



During my researches into the development of double 

 flowers,'-^ I was led to the conclusion that Sachs's theory 

 offers really the simplest expression of the facts. In all 

 these cases the question is one of increase in the quantity 

 of the materials out of which the parts of the flower are 

 formed. This finds expression at one time in the cleavage 

 of the normal layers of the parts, at another in the 

 appearance of new whorls, and again, in the conversion of 



1 Compare Sachs, " Ueber Wachsthumsperioden und Bildungsreize," 

 Nora, p. 217, 1893. 



^ Goebel, "Beitrage zur Kentniss gefuUter Bluthen," Pringsh. Jahrb., 

 xvii., p. 207 ff. 



